In general, plasticizers are used for many products comprising rubber compositions. These migrate with the passage of time, and therefore, there has been the problem of changes in the performance of the product with the elapse of time. To deal with this problem, it is known to add liquid IR or BR, but these are not necessarily covulcanized and considerably migrate.
Further, since these are diene polymers, the heat aging resistance etc. deteriorates.
Further, there is the technique of adding a plasticizer for the purpose of reducing the hardness of the rubber at a low temperature (see Japanese Unexamined Patent Publication (Kokai) No. 6-116443), but the plasticizer per se has a high volatility and migration property, and therefore, there is a large change with time and the performance on ice is considerably decreased. Further, if a large amount of the plasticizer is formulated, there is a problem that the abrasion resistance is also decreased.
Further, there is the technique of formulating a butyl rubber or a halogenated butyl rubber into a tire tread rubber composition so as to improve the grip performance on ice (see Japanese Unexamined Patent Publication (Kokai) No. 60-213506 and Japanese Unexamined Patent Publication (Kokai) No. 5-001177), but there is a defect that the abrasion resistance is conversely decreased.
Further, many plasticizers are used for various types of rubber and resins. Among these, since ester-based plasticizers are in particular superior in compatibility with rubber and resins, they have been used conventionally in the past. However, these ester compounds do not react with rubber or resins or with fillers and migrate to the outside with the elapse of time, and therefore, there was the problem that they caused the physical properties of the rubber or resins to fall with the passage of time. Further, reactive plasticizers for epoxy resins are well known, but almost no reactive plasticizers for other resins or rubber are known.